Parallelizing the Keldysh formalism for strongly correlated electrons

TL;DR

This paper explores the parallelization of the Keldysh formalism to improve the computational efficiency of calculating Green's functions in strongly correlated electron systems, specifically applied to the Falicov-Kimball model.

Contribution

It introduces a parallelization approach for the Keldysh formalism, enhancing the computation of nonequilibrium Green's functions in strongly correlated systems.

Findings

Parallelization improves computational efficiency.

The method accurately computes the f-electron spectral function.

Applicable to the spinless Falicov-Kimball model.

Abstract

Nonequilibrium quantum mechanics can be solved with the Keldysh formalism, which evolves the quantum mechanical states forward in time in the presence of a time-dependent field, and then evolves them backward in time, undoing the effect of the time-dependent field. The Feynman path integral over the Keldysh contour is employed to calculate the strongly correlated Green's function. We examine the accuracy of this procedure for the simplest problem that requires a nonequilibrium formulation: the f-electron spectral function of the spinless Falicov-Kimball model.